The UDS has the following LEDs, which help you diagnose problems.
Power LED (green)
Ethernet 10/100 Link (yellow = 10 Mb/green = 100 Mb)
Ethernet Half/Full Duplex Activity (yellow = Half Duplex/green = Full Duplex)
Diagnostic (red)
Status (green)
Simultaneously lit Diagnostic (red) and Status (green) LEDs mean something is
wrong. If the Diagnostic LED is lit or blinking, count the number of times the Status
LED blinks between its pauses. The following table explains the LED functions: